The Immolator's twin flamers must fire together either as a focused blast or in a wide spread. Focused blast you place the Heavy Flamer template as normal and every model under takes 2 hits. Any partial models, roll a 4+ to see if they are also hit (and taking two wounds). This also causes 2 fire tests to see if the model is lit on fire. If firing the wide spread, place 2 heavy flamer templates side by side. Models that are partially under both templates count as hit (consider the 2 templates as 1 large one). Any that are partial on the edge like normal roll a 4+ to see if hit.
See Codex Sisters of Battle for further fire test rules pg. 47
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